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Articles 1 - 11 of 11
Full-Text Articles in Life Sciences
Non-B Dna-Forming Motifs Promote Mfd-Dependent Stationary-Phase Mutagenesis In Bacillus Subtilis, Tatiana Ermi, Carmen Vallin, Ana Gabriela Regalado García, Moises Bravo, Ismaray Fernandez Cordero, Holly Anne Martin, Mario Pedraza-Reyes, Eduardo Robleto
Non-B Dna-Forming Motifs Promote Mfd-Dependent Stationary-Phase Mutagenesis In Bacillus Subtilis, Tatiana Ermi, Carmen Vallin, Ana Gabriela Regalado García, Moises Bravo, Ismaray Fernandez Cordero, Holly Anne Martin, Mario Pedraza-Reyes, Eduardo Robleto
Life Sciences Faculty Research
Transcription-induced mutagenic mechanisms limit genetic changes to times when expression happens and to coding DNA. It has been hypothesized that intrinsic sequences that have the potential to form alternate DNA structures, such as non-B DNA structures, influence these mechanisms. Non-B DNA structures are promoted by transcription and induce genome instability in eukaryotic cells, but their impact in bacterial genomes is less known. Here, we investigated if G4 DNA-and hairpin-forming motifs influence stationary-phase mutagenesis in Bacillus subtilis. We developed a system to measure the influence of non-B DNA on B. subtilis stationary-phase mutagenesis by deleting the wild-type argF at its chromosomal …
Mfd Protects Against Oxidative Stress In Bacillus Subtilis Independently Of Its Canonical Function In Dna Repair, Holly Anne Martin, Katelyne E. Porter, Carmen Vallin, Tatiana Ermi, Natalie Contreras, Mario Pedraza-Reyes, Eduardo Robleto
Mfd Protects Against Oxidative Stress In Bacillus Subtilis Independently Of Its Canonical Function In Dna Repair, Holly Anne Martin, Katelyne E. Porter, Carmen Vallin, Tatiana Ermi, Natalie Contreras, Mario Pedraza-Reyes, Eduardo Robleto
Life Sciences Faculty Research
Background: Previous reports showed that mutagenesis in nutrient-limiting conditions is dependent on Mfd in Bacillus subtilis. Mfd initiates one type of transcription-coupled repair (TCR); this type of repair is known to target bulky lesions, like those associated with UV exposure. Interestingly, the roles of Mfd in repair of oxidative-promoted DNA damage and regulation of transcription differ. Here, we used a genetic approach to test whether Mfd protected B. subtilis from exposure to two different oxidants. Results: Wild-type cells survived tert-butyl hydroperoxide (t-BHP) exposure significantly better than Mfd-deficient cells. This protective effect was independent of UvrA, a component of the canonical …
Development Of The K-State (Competence) And Mutagenesis In Stressed Bacillus Subtillis Cells, Amanda Kidman
Development Of The K-State (Competence) And Mutagenesis In Stressed Bacillus Subtillis Cells, Amanda Kidman
UNLV Theses, Dissertations, Professional Papers, and Capstones
Mutagenesis is central to the evolutionary process. We currently view evolution as a gradual process affecting all cells within a population. However, my project studied an underestimated part of the evolutionary process: mutations generated during stationary phase (caused by nutritional stress or growth arrest) within a subpopulation of cells. I used Bacillus subtilis, a bacterial model for cell growth and differentiation. Stationary-phase cultures of B. subtilis differentiate subpopulations that exhibit different survival strategies including competence, secondary metabolite production, biofilm formation, cannibalism, and endospore formation. The development of competence permits cells to uptake exogenous DNA and incorporate it into their genome. …
Dna Secondary Structures And Their Contribution To Mutagenesis In B. Subtilis Stationary Phase Cells, Carmen Vallin, Holly Anne Martin, Christian Ross, Ronald Yasbin, Eduardo Robleto
Dna Secondary Structures And Their Contribution To Mutagenesis In B. Subtilis Stationary Phase Cells, Carmen Vallin, Holly Anne Martin, Christian Ross, Ronald Yasbin, Eduardo Robleto
McNair Poster Presentations
It is widely known and accepted that the cause of many mutations in cells are generated during the replication process of actively dividing cells, however more recent research has shown that mutations also arise in non growing conditions, a phenomenon known as stationary phase mutagenesis. Much of what is known come from studies in eukaryotic and bacterial models. It has been proposed that in non-growing cells, the process of transcription plays an important role in mutagenesis. We test the hypothesis that DNA secondary structures, formed during transcription, promote mutagenesis. The transcription-generated structures are speculated to be prone to by blocking …
Stationary Phase Mutagenesis In Bacillus Subtilis: The Interaction Between Transcription And Error-Prone Replication In Conditions Of Stress, Mary Girard, Eduardo Robleto
Stationary Phase Mutagenesis In Bacillus Subtilis: The Interaction Between Transcription And Error-Prone Replication In Conditions Of Stress, Mary Girard, Eduardo Robleto
Undergraduate Research Opportunities Program (UROP)
While under conditions of stress, non-dividing cells may acquire beneficial mutations. This is referred to as stationary phase mutagenesis, or adaptive mutagenesis. Previous research has shown that actively transcribed genes and those under selective pressure are prone to mutations that confer escape from non-dividing conditions. Accordingly, strains lacking transcription factors have shown a drastically lower number of mutations that confer escape while under amino acid starvation than those observed in the wildtype background. Also, error-prone DNA polymerases are known to be active in cells under stress and it has been shown that strains lacking an error-prone DNA polymerase display reduced …
The Role Of Rpoe In Stationary Phase Mutagenesis In Bacillus, Turquoise C. Alexander, Eduardo A. Robleto
The Role Of Rpoe In Stationary Phase Mutagenesis In Bacillus, Turquoise C. Alexander, Eduardo A. Robleto
Undergraduate Research Opportunities Program (UROP)
Stationary phase mutagenesis is a phenomenon whereby random mutations are generated in non-dividing cells. In order to understand how these mutations arise, we use Bacillus subtilis, a gram positive rod-shaped model organism. It is hypothesize that increased transcription promotes stationary phase mutagenesis in this organism. We therefore examined the role of rpoE, a gene that encodes RNA polymerase ! subunit and proposed to influence efficiency of transcription. To this end, we will first generate a strain bearing a deletion in the rpoE gene. In order to determine if this gene is important for mutagenesis, we will examine the accumulation of …
Dna Secondary Structures And Their Contribution To Mutagenesis In B. Subtilis Stationary Phase Cells, Carmen Vallin, Katherine Ona, Chris Ross, Ronald E. Yasbin, Eduardo A. Robleto
Dna Secondary Structures And Their Contribution To Mutagenesis In B. Subtilis Stationary Phase Cells, Carmen Vallin, Katherine Ona, Chris Ross, Ronald E. Yasbin, Eduardo A. Robleto
Undergraduate Research Opportunities Program (UROP)
It is widely known and accepted that the cause of many mutations in cells are generated during the replication process of actively dividing cells, however more recent research has shown that mutations also arise in non growing conditions, a phenomenon known stationary phase mutagenesis. Much of what is known come from studies in eukaryotic and bacterial models. It is proposed that in nongrowing cells, the process of transcription plays an important role in mutagenesis. I will test the hypothesis that secondary structures formed of DNA generated transcription promote mutagenesis. The sequences transcriptiongenerated structures are speculated to be prone to mutations …
The Regulation Of The Icsp Promoter Of Shigella Flexneri By The Virulence Factor Virb, Maria Castellanos, Dustin Harrison, Helen Wing
The Regulation Of The Icsp Promoter Of Shigella Flexneri By The Virulence Factor Virb, Maria Castellanos, Dustin Harrison, Helen Wing
Undergraduate Research Opportunities Program (UROP)
Shigella flexneri is a pathogenic bacterium that causes severe dysentery in humans commonly known as shigellosis. Shigella encodes an outer membrane protease called IcsP. The regulation of icsP expression is under direct control of a transcriptional factor called VirB, which controls the expression of many virulence genes in Shigella. Previous work has shown through deletion analysis of the icsP promoter region that sequences as far as 1368 base pairs upstream of the transcription starting site are important for the regulation of the icsP gene by VirB. However, it is still unclear whether VirB activation requires sequences within the icsP promoter …
Construction Of A Thif Genetic Disruption In Bacillus Subtilis, Kathleen Bradley, Christine Pybus, Ronald Yasbin, Eduardo Robleto
Construction Of A Thif Genetic Disruption In Bacillus Subtilis, Kathleen Bradley, Christine Pybus, Ronald Yasbin, Eduardo Robleto
Undergraduate Research Opportunities Program (UROP)
The goal of our research is to determine whether the level of transcription of a gene is correlated with the level of mutation in that gene. One factor involved in the mutability of a transcribed gene is the ability of the single stranded DNA to form secondary stem loop structures (SLS), in the wake of the transcription bubble, that contain unpaired mutable bases. We are interested in correlating the levels of mutation with transcription in the thiF gene, which is predicted by bioinformatic analysis to be highly mutable. To achieve this goal, Kathleen will first construct a non-polar thiF genetic …
The Effect Of Cody On Stationary Phase Mutagenesis In Bacillus Subtilis, May Yared, Holly Martin, Eduardo A. Robleto, Ronald E. Yasbin
The Effect Of Cody On Stationary Phase Mutagenesis In Bacillus Subtilis, May Yared, Holly Martin, Eduardo A. Robleto, Ronald E. Yasbin
Undergraduate Research Opportunities Program (UROP)
We examine the notion that cells in conditions of stress accumulate mutation is in genes under selection via transcription processes. CodY is a global transcriptional regulator in many Gram positives, including soil and pathogenic microbes. In conditions of exponential growth and when branch chain amino acids and GTP are in abundance CodY acts as a transcriptional repressor of many metabolic operons. This transitional repression saves the cell energy and allows efficient use of resources. In conditions of starvation, CodY relieves repression of genes involved in acquisition of nutrients and degradation of carbon sources (genes under selection). Here, we compare the …
Constructing An Argf- Strain Of Bacillus Subtilis, Allison Faucher, Christine Pybus, Ronald E. Yasbin, Eduardo A. Robleto
Constructing An Argf- Strain Of Bacillus Subtilis, Allison Faucher, Christine Pybus, Ronald E. Yasbin, Eduardo A. Robleto
Undergraduate Research Opportunities Program (UROP)
The goal of our research is to determine whether the level of transcription of a gene is correlated with the level of mutation in that gene. One factor involved in the mutability of a transcribed gene is the ability of the single stranded DNA to form secondary stem loop structures (SLS), in the wake of the transcription bubble, that contain unpaired mutable bases. We are interested in correlating the levels of mutation with transcription in the argF gene, which is predicted by bioinformatic analysis to be highly mutable. To achieve this goal, Allison will first construct a non-polar argF genetic …